battery selector issue 3100SCR

[Oscar Tango]

Shrew - I do have the same setup, same problem and even same boat (minus the genset but that's not really a factor).

cjc357 - would you be able to take a photo of your batteries, and possible the back of your switches? I'm thinking we may have a bad cable, or possibly a bad switch.

I'm going to my boat this weekend and can provide photos (if you'd like) and do some testing on the cables and switches.

[shrew]

@ Oscar Tango. My reply regarding the Generator reply was to the OP. If you have twins with a single Group 24 and 2 group 27's in parallel, that would be an odd setup.

[Oscar Tango]

That is exactly my setup, and I agree it's odd not to mention confusing with the two 4-position switches. I thought it was poor configuration from the previous owner/mechanic until @cjc357 verified his same setup is from the factory.

[2004_3300_SCR]

Here's a picture of the factory wiring diagram from the 2002 3300SCR owner's manual supplement. I'd imagine a similar size boat from the same era would be wired in similar fashion.

The battery switches are not labeled, I'll call the left switch #1 and the right switch #2. Looks like the port battery + connects to battery switch 1's terminal #1 and is also jumped over to terminal #1 on battery switch 2. The output on switch 1 feeds the port engine and generator (if equipped).

The stb. battery + feeds both terminal 1 and terminal 2 on battery switch 2, and is jumped to terminal 2 on the first switch. The output on switch 2 feeds the stb. engine and the house.

A picture is worth a thousand words...and I don't know why, but the picture rotated 90 degrees when I uploaded it.

[cjc357]

The diagram as you mentioned is from a 3300SCR. Thats a different setup and does not match our 3100. I have a friend who has the 3300 it is different.

OT & Shrew - if you guys want to take pics that would be great.. My batteries are sitting in my basement at the moment so thats no help right now.

I think someone asked.. My engine switch does operate properly. I can isolate and start the engines with either battery using the engine switch. This does function properly. With our setup, you CAN NOT isolate per engine.

For whatever reason, I just cant isolate a battery with the house switch.. If we are all experiencing the same problem, my guess is its a wiring config issue from the factory.

[Oscar Tango]

the boats may be different, but at least the 3300 schematic makes sense. I attached the 3100 schematic, and it is showing each engine isolated to each switch. @cjc357, you and I both know this isn't true.

To add to the confusion, the two switches are jumpered via B2, but neither B2 is wired to a battery! And both B1's are wired to both batteries! This makes no sense to me, and tells me the 3100's might be misconfigured from the factory as @cjc357 has suggested.

I'll know more tomorrow, pending good weather I should be in the engine compartment pulling wires and taking photos

[cjc357]

Ya that was is wrong. Let me look though my paperwork. I have some here and at the boat which is covered until next weekend

[cjc357]

OT where you located? How long have you had your 3100?

[Oscar Tango]

This is our 2nd season with the 3100. Love everything about it, except the batteries dying multiple times last season...

[Oscar Tango]

Here's the back of the switch panel. It was tough to access with limited cable slack, but it appears there is a jumper from bat 2 on the top switch to bat 2 on the bottom. I didn't have time to investigate further, looking forward to what you come up with for documentation and any photos you can take to compare.

[cjc357]

Ok thank you. I was down the boat today doing some bottom painting. Im away for the week and next week will be uncovering and starting engines. Ill let you know asap. I see your from warwick. I bought my boat in Wakefield.

[Oscar Tango]

I was able to do some extensive testing over the last few days, here's what I've found.

My 3100 is wired per the DC schematic I posted, with two exceptions; 1 - the schematic only shows two batteries (even though we have three, two port and 1 stbd;the two ports are wired in parallel with stock cables). 2 - the schematic incorrectly labels "Port Battery" and "Starboard Battery" (The port battery feeds only the starboard engine; the starboard battery feeds the port engine, house, and generator, if equipped).

What makes this even more confusing is how the battery switches are labelled "Engine" and "House"; after hours of tracking down cables and testing, I've determined the switch labelled "Engine" is wired to the port battery, and the switch labelled "House" is wired to the starboard battery. Additionally, both switches only have feeds from the one battery (wired to "Batt 1"), so "Batt 2" position does absolutely nothing.

What I ended up doing was moving the house feed from the starboard battery to port. In my setup, this leaves the starboard battery isolated for the port engine and generator. Worst case scenario; the house kills the two port batteries (which also feeds the stbd engine), I still have the stbd battery and can turn on the generator to recharge.

This is extremely confusing and as I write this I'm disappointed with whoever was responsible for designing the DC system. I may completely re-wire the DC system, but for now I think I've got a decent fix until I can get in the water and load test.

I'm still curious to see what anyone else finds for a DC setup in a 3100SCR. In the meantime, I hope this was helpful.